1. Field of the Invention
The present invention is related to a thread tension adjustment device of multi-needle sewing machine, and more particularly to a thread tension adjustment device mounted on one side of the sewing machine. Multiple thread-loosening slide boards are driven by a link to control multiple thread tension adjustment buttons for adjusting the tension of the threads.
2. Description of the Prior Art
FIG. 12 shows a conventional multi-needle sewing machine used in industrial sewing. A thread rack 51 is arranged at a remote end of the sewing machine 52. Multiple reels of threads are fitted on the thread rack 51 and guided to the stitching needles of the sewing machine 52. In order to smoothen the stitching of the thread, multiple thread tension adjustment devices 53 are mounted near the thread rack 51 for respectively correspondingly pressing and clamping the threads. Accordingly, the tension of the threads passing through the needles can be tensioned or loosened.
When it is desired to loosen the thread, via a tread switch (not shown), a link (not shown) on the back of the housing of the sewing machine is driven to pull a steel cord 54 and thus pull all the thread tension adjustment devices 53 away. Under such circumstance, the threads are loosened. The thread tension adjustment devices 53 are mounted near the thread rack 5 arranged at the remote end of the sewing machine 52. Therefore, some shortcomings exist in the sewing machine as follows:
1. The thread tension adjustment devices 53 are arranged at the remote end of the sewing machine 52. In sewing operation, when an operator desires to adjust the tension of some of the threads, the operator needs to extend his/her hand to the remote end for adjustment. This is quite inconvenient.
2. The thread tension adjustment devices 53 is spaced from the sewing machine 52 by a considerable distance so that it is hard for the thread tension adjustment devices 53 to truly tension the threads between the thread tension adjustment devices 53 and the sewing machine 52. As a result, the tension of the threads can be hardly accurately adjusted and the threads tend to be torn down. This leads to inconvenience in sewing operation.